Method for retarding the deterioration of rubber



WILLIAM s. oALc'o'rr Ann WILLIAM- A.- :DoUGLAss, on rnnns Gnovn, NEW JERSEY,

ASSIGNORfi T E. I. DU FONT DE NEMOURS' &; GOMBANY,-OFVWILMINGTON, DELA-' WARE, A CORPORATION OF DELAWARE METHOD FOR RETARDING THE DETERIORATION OF RT JBBER No Drawing".

This invention relates to a method of treating rubber and the resultlng' rubber product and is more particularly concerned and R" represent aryl nuclei which may or 40 been incorporated in ing the deterioration of rubber by the use of a new class of compounds, which not only may be easily and economically prepared 7 from'readily available materials, but which .at the same time do not retard the cure.

With theseobj ects in View it has now been discovered that diaminoand substituted diamino-diaryl-hydrols may be added to a rubber mix without materially affecting the rateof cure and that the resulting rubber product when vulcanized has: much greater resistance to deterioration than rubber con taining no age resisting compounds.

The compoundscontemplated by the invention have the following formula:

wherein A and A represent an amino group, or a monoor dialkyl amino group and B may not contain alkyl or alkoxy substituents. The mannerof preparing compounds of the type indicated by the general formula is fully describedin the prior literature.

In order to disclose thefinvention in, detail, the following example of an actual embodiment thereof is presented. It should be understood, however, that this example is furnished purely for purposes of illustration and that it is not the intention that the in vention be limited to the particular reagents,

Application filed August 30, 1929. Serial No, 389,607.

proportions, or other conditions therein specified. 1 7

Ewmnple 1 Tetrw methyl diam lino benzhy droZ I H 1 I roman-O N CH3) e 1 l Two stocks were made 'up of the following composition; the proportions'are given by weight: 1

18.15 18.15 2,75 2.75 D. Q. I. G 0.5625 0.5625 Antioxldant 0.0 1. O

The stocks were cured for Q0 minutes at 40 lbs. steam pressure and aged in the oxygen bomb at 70 (1, un'deIY'SOO lbs. oxygen pressure. Stock A was completely deteriorated in 3 days, while stock B was not completely deteriorated atthe end of the 11th day when the test was discontinued.

It will be obvious that many other amino compounds of the type indicated by the general formula may be employed in place of the compound of the example. Among such compounds may be mentioned for purposes of illustration the following which have antiaging properties similar to those of tetramethyl-diamino-benzhydrol..

( 1) Y 4 lf-diamino benzhydrol 1 -3: 3'-diarnino-benzhydrol v v Hi I (4) 4 4 -diaminO-3 3-dimethyl benzhydrol H5 on, V

(5) 4-amino-4f-dimethyl amino benzhydrol a i I (6) 3 3-di1ne'thyl-amino-benzhydrol \(C s)2 H 3mm):

' Q O V a c w (7 3 4-dimethyleamino-benzhydrol ons benzhydrol 7 7 H IE3 H Y i T/ v on r V (9) a 41- dimethylamino-Q 2 dimethylbenzhydrol o 1:. CH3 i E (OHshN ,N(CHI)2 '7 bn, (10) 4 :4- dimethylamino-3j 3- dimethylbenzhydrol I (ll) 4 dimethylamino-a diethylaminobenzhydrol i w v i kcHaZN-O-tkO-Ncamn In addition to'the above listed'co'mpounds the reaction products of p-p-dian1ino-benzhydrol and benzyl chloride, ethylene chlorhydrin'or ethylene dichloride have anti-aging properties similar {to those of the products listed. j v i D Many other compounds falling Within the general class described herein could be 7 l named. lhus, the corresponding dinaphthyl i i and phenylnaphthyl compounds; are embraced within the scope. of the invention. Of all these compounds, however, by reason ottheir unusual effectiveness and their economy of a preparation, the tetra-Inethyl-diagnino compounds are preferred and of'this latter class tetra-methyl-diamino-benzhydrol represents :1 the preferred embodiment.

It will be obvious from the above descrip tion that the aryl groups may contain substituentsv such as alkyl and hydroXy substituents without materially altering the value of the compounds, as age inhibitors.

The antioxidants described above may be incorporated into the rubber by any well 7 known means, such as by milling them into the stock upon the rollsof an ordinary mill.

'Moreover, they can'be employed in various rubber compounds and rubber substitutes, such'as, for example, gutta percha, balata,

' and synthetic rubber, and it is therefore to possible to 'use them for the treatment of vulcanized rubber. In such cases the rubber may be impregnated by either dissolving the antioxidant in a solvent, or by employing it in vapor form. c

As many apparent and widely different embodiments of this invention be made without departing from the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims.

We claim: v,

1. The process or increasing the resistance of rubber todeterloration which comprlses incorporating with the rubber a product hav ing the following general formula H7 A R E-RA wherein A and A represent amino groups or monoor d'ialkyl ammo groups, and R and .Ru'epresent aryl nuclei.

2. The process of increasing the resistance of rubberfto deterioration which comprises incorporating with'the rubber tetra-methyh diamino-benzhydrol. V 5

In the art of vulcanizing rubber, the step of mixingwith the unvulcanizedrubber vuloanizing agent and 'a, compound having the general formula V e A-R-d-R A' wherein A and A represent amino groups or monoor dialkyl amino groups, and R of mixing with the unvulcanized rubber a and R represent aryl nuclei, and thereafter vulcanizing.

4. In the art of vulcanizing rubber, the step of mixing with the unvulcanized rubber a vulcanizing agent and a compound having the formula set forth in claim 1, in which formula at least one of A and A represents an alkyl substituted amino rm and thereafter vul-.

canizing.

5. In the art of vulcanizing rubber, the

step of mixing with the unvulcanized rubber a vulcanizing agent and a compound having the formula set forth in claim 1, in which formula at least one of A and A represents a dialkyl substituted amino group, and thereafter vulcanizing.

6. In the art of vulcanizing rubber, the step vulcanizing agent and a compound having the formula set forth in claim 1, in which formula both A and A represent an alkyl substituted amino group, and thereafter Vulcanizing.

7 In the art of vulcanizing rubber, the step of mixing with the unvulcanized rubber a vulcanizing agent and a compound having the formula set forth in'claim 1, in which formula both A and A represent a dialkyl substituted amino group, and thereafter vulcanizing.

8. In the art of vulcanizing rubber, the step of mixing with the, unvulcanized rubber a vulcanlzing agent and a compound having the formula set forth in claim 1, in which formula both'R and R represent phenyl radicals, and

thereafter vulcanizing.

9. In the art of Vulcanizing rubber, the step of mixing with the unvulcanized rubber a vulcanizing'agent and a compound having the V V formula set forth 1n claim 1, n which formula both A and A represent alkyl substituted amino groups, and both R and R represent phenyl groups, and thereafter vulcanizin g.

10. In the art of vulcanizing rubber, the step of mixing withthe unvulcanized rubber a vulcanizing agent and tetra-methyl-diamino-benzhydrol, and thereafter vulcanizing.

11. Rubber having incorporated therewith wherein both A and A represent an alykl substituted amino group, and R and R" represent aryl radicals, and thereafter vulcanizing.

1A. Vulcanized rubber obtained by incorporating therewith a vulcanizing agent and an anti-aging compound having the general formula wherein both A and A represent a dialkyl substituted amino group, and R and R represent phenyl radicals, and thereafter Vulcanizing. l

15. Vulcanized rubber obtained by incorporating with the rubber prior to'vulcanization from 1 to 5% of tetra-methyl-diaminobenzhydrol and 'a vulcanizing agent, and thereafter vulcanizing.

16. In the artof vulcanizingrubber, the

step of mixing with the unvulcanized rubber a vulcanizing agent and 4-4-diamino-benzhydrol, and thereafter vulcanizing.

17. In the art of vulcanizing rubber, the step of mixing with the unvulcanized rubber tures. l

' 'WILLIAM S. CALCOT'I.

WILLIAM. A. DOUGLASS.

an anti-aging compound having the general formula wherein A andA represent amino groups or ,monoor dialkyl amino groups, and R and R represent aryl nuclei. 12. Rubber having incorporated therewith tetra-methyl-diamino-benzhydrol.. 13. Vulcanized rubber obtained by in- ,corporating therewith a' Vulcanizing agent and an anti-aging compound having the general formula I n V AR J-R''A 

